is an inherited disease that can be a
risk factor for developing emphysema and cirrhosis or panniculitus.
The condition occurs when the gene that makes a
protective blood protein called alpha-1 antitrypsin, or AAT, is
defective. Normally, AAT is made in the liver and then travels
through the bloodstream to the lungs, where it keeps lung tissue
healthy by neutralizing an enzyme called neutrophil elastase, which
normally fights off infections and helps clean up dead lung tissue.
When the AAT gene is defective, AAT accumulates in the liver and
can’t make its way to the lungs. Without enough AAT, neutrophil
elastase doesn’t stop working when an infection is cleared, but
instead keeps going, attacking the walls of fragile air sacks in the
lungs called alveoli, which are responsible for exchanging oxygen
from the air we breath for carbon dioxide in the blood. When the
alveoli are damaged, oxygen and carbon dioxide cannot be exchanged
as efficiently, and emphysema is the result. Cigarette smoking
greatly increases the amount and rate of this damage, because
smoking causes more inflammation in the lungs, leading to the
production of more neutrophil elastase.

In most cases, Alpha-1 restricts its damaging
effects to the lungs. In some cases, however, the amount of AAT
accumulated in the liver becomes so large that liver damage results.
Scientists estimate this occurs in about 10 percent of infants born
with the severe form of the disease. However, adults with Alpha-1
may also experience liver problems, including cirrhosis or, in rare
cases, liver cancer.